RNA interference (RNAi) is a system in living cells that helps control genes activity. Mediators of RNAi include two classes of small RNA including microRNA (miRNA) and small interfering RNA (siRNA). Interference RNA molecules have been used to silence genes and consequently their gene products and more efficiently than antisense RNA alone. See Rocheleau C E, et al., Cell 1997; 90:707-716.) Interference RNA molecules have been used to study the role of proteins in signal transduction pathways and it has also been suggested that these molecules might be useful in treating a variety of diseases in which the causative protein is overexpressed. See Arenz et al., Naturwissenschaften 2003; 90:345-359; Coburn et al., J Antimicrob Chemother 2003; 51:753-756. To avoid nonspecific gene silencing induced by longer double-stranded RNA, small interfering RNAs, a duplex of 21-23 nucleotides, have been used as mediators to degrade target mRNA. See Fire et al., Nature 1998; 391:806-811.) Once inside the cell, siRNA is incorporated into an RNA-induced silence complex (RISC), a protein-RNA complex that results in unwinding and strand separation of the RNA duplex. The antisense RNA then guides the activated RISC to anneal and cleave the target mRNA. See Hammond et al., Nature 2000; 404:293-296; Reynolds et al., Nat Biotechnol 2004; 22:326-330; Hammond et al., Science 2001; 293:1146-1150; and Bernstein et al., Nature 2001; 409:363-366.
Both viral and nonviral carriers have been used to carry interference RNA to their cytosolic mRNA target. See Simeoni et al., Nucleic Acids Res 2003; 31:2717-2724. Highly branched HK peptides have also been suggested as carriers of siRNA to transfect eukaryotic cells. See U.S. Pat. No. 7,772,201.
The lipophilic nature of biological membranes restricts direct intracellular delivery of potential drugs or molecular probes. There is a need in the art for transfection complexes having transfection efficiencies sufficient to deliver small RNA into the interior of cells, such as therapeutically effective amounts of siRNA into target cells. There is also a need in the art for carriers that are stable in serum for delivery systems to be effective both in vitro and in vivo.
It is a further object of the present invention to create complexes of RNA with rosette nanotubes that can be delivered into target cells where the RNA can then function to silence certain RNA and thereby prevent expression of an associated protein or proteins. It is a further object of the present invention to provide methods of treating individuals using a delivery system of a complex of RNA with a rosette nanotube which transfects cells of the individual in a manner to prevent expression of an associated protein or proteins. These and other objects, features, and advantages of the invention or certain embodiments of the invention will be apparent to those skilled in the art from the following disclosure and description of exemplary embodiments.